Common Misconceptions of Air Treatment Methods
It is no secret that school bus transportation has been the missing link in the pathogen mitigation process of our school systems. The reasoning for this is that there are many products promising a safer environment, however, the science of their products fail to provide a complete and effective solution. This page will review the most commonly offered air treatment methods.
Installing UV Bulb within existing Air Distribution System.
Installing a UV-C bulb or other antimicrobial bulb “haphazardly” within a buses existing air distribution system or installing a small blower fan unit in the rear of the bus with a UV-C light unfortunately is not a global and effective solution and may actually be a false sense of security. This air distribution system is further mixing the air by creating additional vortexes. It is drawing air from different corners of the cabin across the faces of passengers without a controlled return this causing the aerosol to travel across the airways of other occupants.
Filtering Pathogens (Covid-19)
The COVID-19 Virus is 100 nanometers (nm) wide, to put this in perspective, a human hair is 80,000 to 100,000 nanometers wide. The most common MERV 13 filter and Hepa filters are rated for .3 microns (300 nm), however, the COVID-19 virus is about .1 microns (100 nm), so filters they cannot be expected to function at a satisfactory level(see sources at bottom of this page). In addition, there are many other viruses that are much smaller than the COVID-19 virus and also able to pass through all practical filters. In addition to these simple performance limitations is the fact that filters can be a substantial reoccurring life-cycle expense.
Ion Generators
Ion generators can cause irritation to the respiratory system of children, especially those with asthma or pre-existing respiratory conditions. Recently released data by major universities concluded that ionizing devices that they tested were ineffective in reducing small particles and had an unintended consequence of increasing some levels of dangerous VOC’s. Some members of ASHRAE’s epidemic task force have written an open letter asking school systems not to purchase these electronic air cleaners and to turn them off if they’ve been installed. The letter was endorsed by many scientists and health professionals and it has prompted class action lawsuits against some companies making these devices”. (see sources at bottom of this page)
Chemical Mists (Fogging)
Subjecting youth’s developing respiratory systems to harsh chemicals can have unwanted side affects and should be carefully considered before implemented.
Alternative Antimicrobial Bulb Types
UV is the only air cleaning technology specifically recommended as a supplement by the CDC. UV light has been used and studied for over 120 years to effectively and safely inactivate pathogens. The UV light spectrum is segmented into 3 types and measured in nanometers (nm) by wavelength. The wavelength of 254 nm have proven to be the most effective range in deactivating viruses, bacteria, etc.
This industry standard of 254 nanometers (nm) UV lamps emit ultraviolet UV radiation in the UVC range most lethal for a virus and omit the least ozone biproduct.
Anything less than 250 nm is not going to be effective in deactivating most pathogens. In addition to the bulb performance is the exposure of the air and pathogens to the bulbs radiation to ensure maximum treatment. Just installing a bulb into a fan box is not going to guarantee a specific outcome or that all-of-the air has been treated.
The degree of inactivation by ultraviolet radiation is directly related to the UV dose applied. The UV dose is the product of the UV intensity (I) and exposure time (T), where: DOSE = I X T.
With our patented Serpentine system and multiple bulb exposure, we are maximizing the DOSE and accompanying sterilization process.
UV light in the effective 254 nm range as well as any UV lighting below 400 nm is not visible by the human eye.
